The 3rd Generation Partnership project 3GPP has specified methods that allow a wireless communication device to discover and preferentially select for connection from available non-3GPP wireless access networks such as Wi-Fi type networks. In particular, 3GPP technical specification 23.402 provides for an Access Network Discovery Selection Function (ANDSF), which is an optional policy-provisioning element in the 3GPP network architecture which contains data management and control functionality necessary to provide network discovery and selection assistance according to a network operator's policy. The ANDSF may respond to requests from a wireless communication device for access network discovery and selection information in a pull mode, and may be configured to initiate such data transfer to a wireless communication device in a push mode.
The ANDSF may provide to the wireless communication device one or more inter-system mobility policies for use if and when a device can route IP traffic over a single radio access interface at a given time, or one or more inter-system routing policies for use if and when a device can route IP traffic simultaneously over multiple radio interfaces. Such policies may define, for example, at what times and locations the wireless communication device may use or move between particular access networks or networks of particular technology types, and/or to select the most preferable access technology type in general or in particular circumstances. For example, an inter-system mobility policy may indicate a list of wireless access networks with priority order (as preferred by the mobile operator to be accessed) and with validity information (e.g. location or time of day) indicating when this policy is considered valid. A wireless communication device provisioned with such inter-system mobility policy should attempt to access the operator's core network by using the highest priority wireless access network as indicated by the policy, whenever this policy is valid.
3GPP technical specification 24.312 describes an ANDSF Mobility Object (MO) which conforms to Open Mobile Alliance (OMA) Device Management (DM) protocol specifications. The MO provides relevant parameters for inter-system mobility policy, inter-system routing policy and access network discovery. The inter-system mobility policy information consists of a set of one or more inter-system mobility policies. At any point in time at most only one policy is applied in the wireless communication device, and referred to as the “active” policy. Each policy has a number of validity conditions, such as device location and time of day which determine whether the policy may be valid, and a number of results, such as which wireless access technologies or networks are restricted or preferred (in priority order), which are applied when the policy is active. Policies also have associated priorities, so as to determine which of several potentially valid policies has the highest priority and should be considered as active in preference to other potentially valid policies.
When one or more networks become congested in particular areas it would be desirable to change the ANDSF policies at wireless communication devices in those areas to alleviate the congestion and to take advantage of less congested access network resources. However, requiring the network to regularly “push” new policies to a large number of handsets to implement such a scheme is not practical.
It would be desirable to address problems of the related prior art, for example to provide improved selection by a wireless communication device from available wireless access networks.